Mammography is the current imaging method of choice for breast cancer screening. However, it is a suboptimal technique in terms of breast cancer detection with up to 30% missed cancers reported in screening. Two important reasons for non-detection of cancer are the superimposed tissue when applying 2D imaging (mammography) to a 3D object (the breast), and certain cancer growth patterns and subtle differences in physical properties between some tumors and normal tissue. To reduce the superimposed tissue effect, breast tomosynthesis has been developed. Breast tomosynthesis employs a semi-3D technique that improves depth resolution by providing thin slices of the breast, using low dose levels of radiation similar to digital mammography.
In principle, a mammography apparatus for detecting malignant lesions in a breast comprises an x-ray source and an x-ray detector that cooperates for providing an x-ray image of the breast. The breast is inserted into a compression device wherein it is pressed by means of a paddle against the x-ray detector. By the compression, the breast is flattened in order of getting a proper x-ray image. By the compression, the image quality may be improved by increased breast tissue separation. Further, scattered radiation may be reduced and the radiation dose to the breast may be minimized. Mammographic imaging systems have undergone remarkable improvements, but the compression device has remained basically unchanged since modern mammography was introduced in the sixties.
A high attendance in a screening program is a key factor in order to achieve reduced breast cancer mortality. Still, according to studies, many women refrain from attending the screening due to the pain experienced during the breast compression.
In addition, the compression device is inefficient in terms of fixating the breast and providing proper breast compression. It is has been noted that generally high pressure is applied not only to the breast as such but also to the pectoral muscle and nearby tissues. Excessive applied force does not only cause unnecessary pain, but does also fail to reduce tissue thickness.
US 2013/0028373 A1 discloses one example dealing with this issue. The document suggests a solution wherein the mammography apparatus has a contact measuring unit for measuring the contact area between the breast and the paddle. At least one sensor is used to measure the force that is applied to the breast. The force together with the contact area provides the average pressure that is applied to the breast. The average pressure can then be controlled at a pre-established level so as to avoid un-necessary and avoidable pain during imaging.